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SyneRBI / SIRF

Main repository for the CCP SynerBI software
http://www.ccpsynerbi.ac.uk
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add OSSPS set_relaxation_gamma #1204

Closed KrisThielemans closed 7 months ago

KrisThielemans commented 12 months ago

Fixes #1203.

@evgueni-ovtchinnikov I made a start with this. Would you be able to finish it off, and add a quick test?

evgueni-ovtchinnikov commented 12 months ago

testing: what value of gamma would be realistic and what effect to expect?

KrisThielemans commented 12 months ago

https://stir.sourceforge.net/documentation/doxy/html/classstir_1_1OSSPSReconstruction.html says alpha~1 and and gamma ~ .1. Those are the defaults in STIR, so I guess SIRF. Higher gamma means slower convergence (as step-size goes down), but more subset fluctuations.

In any case, I think the test could simply be to set and then get.

Bu the way, there's an upper_bound that would also be useful to expose.